1. Field of the Invention
The invention relates to a seal for a fluid filter and, more particularly, to a seal for a spin-on type oil filter.
2. Summary of Related Art
Spin-on oil filters are well known devices often used in the lubrication system of internal combustion engines. These filters generally include an outer container and an end cover enclosing a hollow cylindrical filter element. An annular gasket is utilized for effecting a seal between the end cover of the filter and an engine block or adapter plate or the like on which the filter is used. Generally, a rectangular lathe cut gasket is disposed within an annular recess formed in the end cover. One or both sidewalls of the recess is then crimped to retain the gasket therein.
Such sealing gaskets are disadvantageous in that the gasket is prevented from rotating relative to the end cover. Once the gasket has made contact with the sealing base, the gasket is subjected to a shearing strain as the filter is rotated into final, operative position, despite the fact that the gasket is typically lubricated prior to installation. The development of such internal shear in the gasket may result in the gasket becoming dislodged and the failure of the seal.
In filters utilizing such sealing gaskets, there is also a tendency for air to become trapped between the gasket and the end cover upon installation. The trapped acts like a spring, so that once the air escapes, the effective torque applied to the gasket is reduced. This allows the filter to loosen due to vibration, and may even result in the filter becoming disengaged from the mount.
Some more recently developed filters have utilized a substantially round sealing gasket having a lip extending radially inwardly and tangentially therefrom. The gasket is retained by a portion of the end cover which is crimped to loosely engage the lip. The gasket is thereby capable of rotation relative to the end cover, limiting the internal shear experienced by the gasket during installation.
These sealing gaskets, however, cannot be used with conventional spin-on filter end covers. Additionally, such gaskets are difficult to automatically install in the end cover, and require proper face orientation prior to installation. Should such a gasket become dislodged, it is also difficult to reinstall by hand. Finally, the extended lip formed on these gaskets appears to be susceptible to cuts and tears, especially if not properly seated.